


Flashback

by omegadeanlovesalphacas



Category: Supernatural
Genre: Alpha Castiel, Alpha Castiel/Omega Dean Winchester, Alpha rut, Dubious Consent, First Time, Human Castiel, Knotting, M/M, Mating Cycles/In Heat, Omega Dean, rape flashbacks
Language: English
Status: Completed
Published: 2016-11-03
Updated: 2016-11-03
Packaged: 2018-08-28 19:33:19
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 640
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8460277
Author URL: https://archiveofourown.org/users/omegadeanlovesalphacas/pseuds/omegadeanlovesalphacas
Summary: Season 5 AU. When Cas knots Dean for the first time, Dean can’t help but get flashbacks of Hell and Alastair.





	

**Author's Note:**

> Warning! This is an Alpha/omega kink prompt fill. Expect more porn than plot, and lots of power imbalance between Cas and Dean. Mind the warnings and kinks in the tags.
> 
> Anonymous asked:  
> If you're still in the mood for dark prompts: s5AU When Cas begins to Fall, he experiences going into rut for the first time when Dean's heat hits. Dean planned on picking up an alpha/getting Cas laid anyway, so figures why not kill two birds. Cue Cas being kinda rough. Dean's all for it until he realizes just how strong Cas still is. Dean flashes back to Alastair and panics, but Cas is too far gone and doesn't realize Dean's sobbing and shaking 'til they're knotted. How Cas reacts is up to you.
> 
> Filled on Tumblr, September 2014.

Dean could feel his heat coming on. He needed an Alpha. He was just thinking about going out to a bar to find one when Cas walked into his bedroom.

Castiel frowned down at himself. “I feel… warm.” He shifted at looked at Dean with confusion. “I think my body is craving physical contact.”

A rueful grin spread across Dean’s face. “You’re going into your first rut, Cas. I can smell it.”

Cas nodded seriously. “That does explain why my penis is hard.”

Dean laughed. “Don’t ever say that again.” He crossed the room, grabbing Castiel’s wrist and tugging him back toward the bed. “My heat’s about to start. What do you say, two birds, one stone?”

Castiel frowned. “I don’t understand.”

Dean rolled his eyes. “Do you want to fuck me until my heat and your rut are done?”

“Ahh, yes.” Castiel nodded again. “That sounds very agreeable.”

Dean laughed. “For the love of… Just shut up and fuck me.”

They started out slowly, kissing and touching. Dean stripped Castiel of his clothes and Cas did the same to him. But Cas’s rut was coming on fast, so  it was only a couple minutes later that Dean found himself pressed to the bed on his stomach as Castiel’s hard cock pressed into his wet hole. 

Castiel let out a long groan of pleasure, then without warning began to fuck into Dean at a startlingly fast pace. 

Dean grunted in surprise. “Woah, Cas…” But his objections were muffled as Cas suddenly pressed his face into the pillow. The Alpha’s other hand hauled Dean’s ass up, forcing the omega into a proper breeding posture. Castiel thrusted into Dean even harder, hip and balls slapping against Dean’s ass with each stroke. 

It was just like Alastair. It _was_ Alastair, Dean was suddenly sure of it. He must have possessed Cas, Dean didn’t know how, but he must have. Alastair was going to claim him and torture him and kill him. Oh god, the knot, the knot, he could feel the knot. He didn’t want to be knotted to Alastair, _not again._

Castiel was overcome by pleasure as he fucked Dean, he’d never known sex could be so amazing. The harder he thrust the better it felt, and for the first time he understood his new Alpha instincts. Forcing Dean under his control sent lust and power singing through his veins. It was finally with a loud groan that Castiel came, his huge knot stretching the omega wide and tying them together.

It was only then that Castiel realized Dean was shaking and crying.

“Dean. Dean, what’s wrong?” Castiel released his hold on the omega, turning them both so that they were spooned on the bed, still tied together. He went to wrap an arm around Dean but he shied away from Castiel’s touch. 

Dean’s eyes were shut tight and his voice shook with fear. “No, Alastair, please, no.” 

Castiel’s stomach sunk. “Dean, I am not Alastair. It’s me, Castiel.” He gripped the handprint on Dean’s shoulder. “It’s Cas.”

Dean’s breathing leveled and his tears became sniffles. “Cas?”

“Yes, Dean.” Castiel reached around to wipe the tears from Dean’s face. “I believe that my first rut may have been more than I was prepared to handle. I lost control. I am so sorry, I never wanted to hurt you.”

“Didn’t actually hurt that bad.” Dean’s voice shook a little. “It’s just, the last person who fucked me so rough… I was so sure it was…”

“I know, Dean, I know.” Castiel kissed the back of Dean’s neck. “This was a bad idea, as soon as my knot releases you I will leave you alone.”

Dean took a deep breath. “No.” He looked back at Cas. “Maybe we could just start over?”

Castiel gave him a small smile and nodded. “I would like that.”

**Author's Note:**

> Thanks for reading! Comments are love! <3
> 
> Visit me on Tumblr: [omegadeanlovesalphacas.tumblr.com/mobilemenu.](http://omegadeanlovesalphacas.tumblr.com/mobilemenu)


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